Which IP addresses need access to my SMTP/IMAP server?

Most email server configurations will not need to care about IP addresses. However, if you are in a corporate/IT environment where you can only give specific IP addresses access to your SMTP/IMAP email servers, you can use this list below.

52.27.236.234

52.32.48.248

54.71.177.103

However, please note that these IP addresses may change in the future, without warning, so keep this in mind if your email syncing/sending stops working at a future date.